I am in the process of putting a '99 in an '00. Couple things that I think you are not aware of. First a '98 into '00 would not be plug and play. Out of the 2 connectors one connector is different. The bigger one. So you have to unpin yours and repin it to the '98 harness. If you look under your dash under the glove box you will see a piece of black plastic that is kind of circular in shape. the bigger plug is behind it. The smaller plug, 3 wires, is in the fuse box. At least I am pretty sure. One of the little ones at the top I think. The wires are the same color and if you pick the wrong spot thinking you will not be able to put it in. Second do you have lighted vanity mirror visors in your '00? If so did you grab the visors from the '98? Cause that is a different connector too. at least I think it is having never seen a '98 harness. My guess is it is the same as a '99. So the thing with the visors is that '99, so I am guessing '98 is the same, have an internal ground. There is just one wire in the harness going into the visor for power. '00's are a two wire set up. Both power and ground wires. Having the visors from the '98 would make it plug and play on that end. You can figure out some way to ground it out. For instance you could cut the visor connectors off your dome light harness, remove the power wire from the cut off connector, remove the power wire from the '98 harness, repin that into the '00 connector and take the short ground wire and just ground it somewhere. Did you grab the bracket and temp sensor? I can't post pictures on this forum like I can on other ones. Or at least can't figure out how. Cause I do have some pictures that would explain some of the things I mentioned a little better. If you want I could email them to you. Just PM me.